It's said that we're all our own worst critics. While that's probably not as true as one would like to think, I'd feel pretty confident in saying that most people have things about their own writing that drive them up the wall, or atleast bug them a little bit, and that certainly extends to roleplay, as well.
But. Both for the sake of personal comfort and self-improvement, I find it often helps to talk about that sort of thing. So, what about your own roleplay, either in terms of just little quirks or overall style, annoys you the most?
For me, personally, there's always been two things.
1. I'm a slow typist. Not massively so, but enough that in fast paced roleplay - Especially one with a lot of participants - I usually end up falling behind, or having my character frequently cut off in the middle of their points because people assume I've finished. In order to try and compensate for this, I often end up typing everything my character has in mind to say in one big block of probably slightly obnoxious text as opposed to breaking it down into smaller, better-flowing chunks, which frequently does more harm then good when the topic has already shifted forward. Or, alternatively, rushing faster then I can manage, and forgetting/misusing words.
2. I tend to repeat myself. Not in the sense that I'll literally say the same two things twice, but rather that I'm prone to getting fixed on a few lead-in's and lead-out's in any given session. For instance, I might start three posts in a row with my character saying "Well, I..." or several finishing with "...you know?" I also might just use a descriptive word an excessive number of times. And somehow, I don't notice any of this until I'm looking back after the fact and wishing I had some sort of time-warping edit button.
I suppose both of those are largely broad issues, but feel free to talk about how you feel limited by your own character, or anything more specific, as well.